From the perspective of a hunter, photographer or naturalist, a portable tree stand should be a light-weight device that can be easily carried for long distances over rough terrain, and easily erected and safely secured to a tree trunk or similar upright object, even in the dark. Also, the tree stand should have a seat that allows the user to sit safely and comfortably for several hours. Should the need arise, the user should be able to disassemble the stand and move it to another location quickly. For deer hunting in particular, the ability to move the stand quickly to new locations is very important and sometimes it is critical for the hunter to be able to move his stand quickly by a distance of only a few yards. Furthermore, the stand should be capable of being secured to a tree trunk in such a manner that, after it is disassembled and removed, no signs remain that would be detectable by wildlife or other persons. The portable tree stand should also be adaptable to be secured to the trunk of a tree of a wide variety of types, shapes and locations. In addition, the tree stand should be capable of being easily ascended and sat upon.
Portable tree stands fall into four general categories. One category consists of collapsible ladders, with platforms at their top ends that fasten to the tree trunk. Examples of the ladder stands are shown in U.S. Pat. Nos. 3,630,314; 4,552,247; and 5,105,908. The main disadvantage of ladder stands is that they are heavy and bulky, making them difficult to carry. They are also prone to catching on branches and other forest clutter and are noisy when they are disassembled, moved and reassembled. Furthermore, they require, for stable placement, a tree that is relatively thick, preferably 12 to 18 inches in diameter at the place where the platform at the top of the ladder is to be connected, in order to enable the ladder to resist the twisting movement of the user's weight. Alternatively, the ladder type of stand should be secured to a tree with a double trunk.
Another type of portable tree stand is the climber stand. A climber stand comprises a U-shaped arm that wraps around the tree trunk and is pivoted to platform with a wedge-shaped end that engages the trunk below the arm. The weight of the platform and, at some times, the user's weight on the platform causes the platform to press against one side of the trunk while the pivoted arm engaging the other side of the trunk prevents the end of the platform away from the trunk from falling downward. The stand can be moved by the user holding onto the trunk with either pair of limbs, either his arms or legs, while he disengages the wedged platform with his other pair of limbs and moves the stand up or down the trunk. In some cases, two stands are used, and the user moves one stand while hanging on to the other stand. Examples of climber stands are shown in U.S. Pat. Nos. 4,427,092; 4,989,766; and 5,016,733. Climber stands are generally heavy and bulky, because they have cantilevered support members that must be sturdy enough to support the users who is climb on them. They also require very straight, vertical tree trunks of 10 to 18 inches in diameter. Furthermore, the user must be strong and very athletic in order to climb quickly up and down trees using a climber stand. In addition, a climber stand tends to be noisy while the user is climbing on it and it can be dangerous if the user does not hang or sit on it properly.
Another type of tree stand is the clamp-on stand. Many of these stands are of construction similar to the climber stand. However, the clamp-on stands are secured more permanently to the tree trunk and are not designed for use in climbing the tree. Examples are shown in U.S. Pat. Nos. 4,411,335 and 5,060,756. The clamp-on stands are generally lighter in weight and less bulky than the climber stands. However, because the user must carry additional apparatus for climbing the tree, the total package is usually heavier and more bulky than a climber stand. In addition, the clamp-on stands tend to be more difficult to attach and remove from trees, making them less useful as portable devices.
The fourth type of portable tree stand is the single pole stand. This stand comprises a long upright pole with steps protruding from its sides. The top of the pole is equipped with an clamping assembly for securing it to a tree trunk. For storage purposes, the pole is divisible into sections and the steps are usually removable. Some single pole stands are climbing devices only and have no means for the user sitting on them. They are usually intended for use with a clamp-on stand, as shown in U.S. Pat. Nos. 4,411,335; 5,040,635; and 5,109,954. Others are equipped with seats, as shown in U.S. Pat. Nos. 4,257,490 and 4,592,446. All of these stands are heavy and cumbersome to carry because of the many steps that protrude from them. Those that have removable steps are less cumbersome to carry, but they are more difficult to assemble, particularly at night. The pole stands with no seats are cumbersome because additional seats must be carried with them and attached separately to the tree trunk. The stands that do have seats have heavy and cumbersome systems for securing them to the tree trunks.
In the building industry, various climbing devices are used for mounting scaffolds, such as the portable step shown in U.S. Pat. No. 4,754,841. However, such steps rely on sharp prongs for their attachment and are designed for use with wooden posts of uniform size that can withstand the biting engagement of prongs. In contrast, a portable tree stand must be designed for climbing irregular tree trunks that would be damaged by the repeated piercing of prongs.